Wfj. Parsons et M. Keller, CONTROLS ON NITRIC-OXIDE EMISSIONS FROM TROPICAL PASTURE AND RAIN-FOREST SOILS, Biology and fertility of soils, 20(3), 1995, pp. 151-156
In field studies, forest soils in the Atlantic Lowlands of Costa Pica
emitted greater amounts of nitric oxide (NO) than soils from pastures
that had been actively grazed for over 20 years following their conver
sion from forest. We measured NO production from intact soil cores fro
m these land uses. Laboratory tests using ammonium (NH4+), nitrate (NO
3-), nitrite (NO2-), water, and acetylene (C2H2) additions demonstrate
a response consistent with field studies. Forest soil cores produced
more NO than pasture cores regardless of treatment. In forest soil the
response to NH4+ solution was significantly greater than response to
water or an ambient moisture control. Addition of 10 kPa C2H2 caused a
marked decrease in NO production in forest soil cores. These response
s suggest a nitrification-linked control over NO production. Large and
rapid responses to NO2- additions suggest that chemical decomposition
of this ion may contribute to NO production. Pasture soil cores did n
ot show a significant response to any of the treatments including NO2-
. Low porosity in the pasture soils may restrict emission of NO produc
ed therein.